In order to explore the status of soil heavy metal pollution and environmental quality in west Hunan, relevant areas of Phoenix County were selected as the study area. Using data from 440 soil samples collected in the study area from June to August 2022, the pH value of the soil and contents of eight heavy metal elements, namely, As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, were analyzed. The PMF model was used for traceability analysis and geochemical evaluation of soil environmental quality. The results showed that the average values of soil heavy metals ω(Zn), ω(Cr), ω(Pb), ω(Ni), ω(Cu), ω(As), ω(Cd), and ω(Hg) were 81.02, 64.67, 31.63, 29.27, 25.52, 9.93, 0.28, and 0.13 mg·kg-1, respectively. The soil in the study area was mainly weakly acidic, and the contents of the Cd and Hg elements were relatively high compared to the national soil background values and were highly variable. The contents of the Hg and Cd elements in forest land were higher than that in other land uses. The PMF model results showed that the contribution rates of heavy metal pollution sources in the study area were mining sources (37.4%), atmospheric sedimentation sources (7.7%), natural sources (41.1%), and agricultural activity sources (13.8%) and provided suggestions on pollution control measures according to the spatial distribution of the four types of pollution sources. Through the comprehensive assessment of soil environmental geochemistry, the study area was divided into three types of plots, namely, non-risk areas (94.27 km2), accounting for 76.38%; risk-controllable areas (27.45 km2), accounting for 22.24%; and high-risk areas (1.7 km2), accounting for 1.38%. This study provided data support for the prevention and control measures of land pollution in the research area, as well as the delineation of the prevention and control scope.

Marine Protected Areas (MPAs) are designed to conserve biodiversity and vulnerable ecosystems. This study aimed to assess the environmental quality of three Brazilian MPAs, based on the integrated analysis of biomarkers in pufferfish. The MPAs are differentiated by the degree of anthropogenic influences. The Barra do Una Estuary sustainable reserve (JUR) is a reference area due to its low levels of contamination and species diversity. The Cananéia Estuarine System (CAN) has been recognized as a biosphere reserve by UNESCO, as well as a Ramsar wetland. This MPA was influenced by upstream mining activities, resulting in the introduction of metals in the estuarine waters and the discharge of untreated urban sewage. The São Vicente estuary (SSV) lacks proper sanitation infrastructure. All collections were conducted during winter season, and, after collection, the animals were euthanized, their soft tissues were removed, and multiple biomarkers were analyzed in the gills and liver, as biometric, genotoxic, biochemical, and morphological. A one-factor multivariate analysis was applied to evaluate the differences between the data sets, and the matrices were analyzed using PERMANOVA to evaluate the \"estuary\" factor. The results were integrated using PCA with a 0.4 cut value and an Enhanced Integrated Biomarker Response (EIBR) was calculated. PCA was correlated with biochemical, genotoxic, and morphological biomarkers. In general, SVV differed from CAN and JUR as shown by both univariate and multivariate analyses. SVV also showed the highest EIBR, followed by CAN. Organisms from SSV showed greater gill pathology, elevated AChE activity and lipoperoxidation (LPO), and micronuclei frequency. CAN present intermediate EIBR, with severe pathologies in the liver. CAN seems to present an intermediate environmental quality between SSV and JUR indicating the importance of the existence of MPAs for environmental conservation and the need to monitor such areas, to maintain their suitable environmental quality.

Free-living marine nematodes are valuable biological indicators for different environmental disturbances. Their taxonomic composition and functional traits often respond to environmental changes. In this study, marine nematodes, collected from the Bohai sea on the northeastern coast of China in 2014, were investigated in terms of their taxonomic composition and functional traits. Furthermore, the environmental quality of the investigated area was assessed based on nematode metrics. The studied nematode community showed spatial variation in taxonomic and functional composition, in response to changes in environmental variables such as sediment chlorophyll-a, phaeophytin-a, organic matter content, silt-clay content etc. Overall, high percentage of tolerant marine nematodes species or colonizers predominated, suggesting a disturbed environmental condition of the study area. Further results from the environmental quality assessment based on nematode metrics indicated a moderate quality status at the most investigated stations.

Free-living nematodes were investigated in three Mediterranean commercial ports (Ancona and Trieste, Italy; Koper, Slovenia) in terms of abundance, diversity and functionality. Results indicated that r-strategist genera were dominant in all ports and that a more diverse assemblage characterized Trieste, despite the high contamination levels, suggesting a potential adaptation to long-standing contamination. The main environmental factor that shaped the assemblage in all ports were Total Polycyclic Aromatic Hydrocarbons, while Total Organic Carbon and the grain-size were less relevant. A co-occurrence analysis was applied for identifying which genera cohesively respond to site-specific environmental conditions in order to recalibrate and implement the sets of bioindicator genera in relation to their different opportunistic behaviour. Finally, we provided some suggestions for a proper application of the nematode indices (Maturity Index, Index of Trophic Diversity, Shannon diversity) in order to encourage the use of free-living nematodes for the environmental quality assessment of commercial ports.

The rapid urbanization and industrialization of Kuwait and the consequent effluent discharges into marine environments have resulted in a degradation of water and sediment quality in the coastal marine ecosystems such as in the Kuwait Bay. This study investigates the ecological response of benthic foraminifera (protists) to environmental stress in the Kuwait Bay. The traditional morphological approach was compared to the innovative environmental DNA (eDNA) metabarcoding to evaluate the ecological quality status (EcoQS). Forty-six surface sediment samples were collected from selected stations in the Kuwait Bay. To detect the pollution gradient, environmental parameters from water (e.g., salinity, pH, dissolved oxygen) and sediment (e.g., grain-size, trace metals, total organic carbon, total petroleum hydrocarbons) were measured at each station. Although the foraminiferal assemblages were different in the morphological and molecular datasets, the species turnover was congruent and statistically significant. Diversity-based biotic indices derived from both morphological and metabarcoding approaches, reflect the environmental stress gradient (i.e., organic and metal contaminations) in the Kuwait Bay. The lowest values of EcoQS (i.e., bad to poor) are found in the innermost part (i.e., Sulaibikhat Bay and Ras Kazmah), while higher EcoQS values occur in the outer part of the bay. This study constitutes the first attempt to apply the foraminiferal metabarcoding to assess the EcoQS within the Arabian Gulf and presents its advantages compared to the conventional morphological approach.

Contamination in estuarine regions affects the local biota damaging the ecosystems and reaching humans. The gastrointestinal tract is a dynamic environment capable of obtaining nutrients and energy from food while it protects the host against harmful toxins and pathogens from the external environment. These functions are modulated by the enteric nervous system and changes in its structure can result in gastrointestinal disorders. The objective of this study was to evaluate if the environmental contaminants have effects on the myenteric neuronal plasticity of pufferfish Sphoeroides testudineus. Animals were collected in Barra do Una River, located at Jureia-Itatins Mosaic of Protected Areas (reference area - RA) and in the Santos Estuarine System (impacted area - IA). Morpho-quantitative analyses of the general and metabolically active myenteric neuronal populations of the proximal and distal intestine were made. Disarrangement was observed in the general organization of the myenteric plexus, with an expressive reduction of the neuronal groups (nodes) in the animals of IA. The vulnerability of the myenteric plexus was evidenced by a decrease in density and cellular profile of the general neuronal population, followed by an increase of the metabolism of the remaining neurons, which in turn was verified by a growth of the area of the cellular and nuclear profiles of the metabolically active neuronal population. Through these analyses, we concluded that animals inhabiting polluted regions present alterations in the myenteric neuronal plasticity, as a way of maintaining the functions of the gastrointestinal tract.

The Danube River is a large transboundary river with many tributaries. Pollution from industries, municipal wastewater and navigation is discharged into the river directly or via its tributaries. These discharges can adversely contribute to the water and sediment quality, posing a risk to aquatic life. Contaminants with low water solubility tend to accumulate in suspended solids, which deposit in riverbed sediments. Subsequently, their levels in sediment represent a time integrated sample indicating the pollution in the watercourse. However, total concentrations in sediment do not directly represent the exposure risk to aquatic life as accumulation in sediment heavily depends on its properties, i.e. the amount of organic material and its composition, which is difficult to characterize as any natural material. To provide contaminant concentrations on a defined basis, surface layer riverbed sediment samples collected at eleven locations along the Danube stretch in the territory of Serbia in 2012, were ex-situ (in the laboratory) equilibrated with silicone passive samplers of constant accumulative properties, using the multi-ratio equilibrium passive sampling approach. Contaminant\'s equilibrium concentrations in passive samplers are mutually comparable in time and space and are better measure for bioavailability than total sediment concentrations. Uptake in the passive sampler converted to equivalent freely dissolved (pore-) water concentrations agreed well with those obtained from surface water passive sampling carried out within the Joint Danube Survey 3 in 2013. Furthermore, equilibrium passive sampler PCB concentrations, converted to lipid-based concentrations, agreed well with concentrations measured in fish sampled in the Danube several years earlier. Out of eleven priority substances, only fluoranthene exceeded the EU EQS in water, while the EQS for biota was exceeded or approached for fluoranthene and benz[a]pyrene, and hexachlorobenzene.

In this study, we used GIS to assess heavy metal concentrations and their spatial variations in Beijing\'s suburban farmlands. The Beijing soil heavy metal background values (background values), the primary standard of the Chinese Environmental Quality Standard of Soil (primary standard), and the Environmental Quality Standard of Green Food Production Site (green standard) were used as the standards for assessing soil heavy metals. Results showed that the average Hg value was higher than that of the primary standard. The Ni and Pb values were lower than the corresponding background values. From the percentage area, the concentration is 100% area with As, more than 93% area with Cr, Cu, Pb and Zn, and 67% area with Cd and Hg, meeting the primary standard; over 97% area met the green standard. The calculated Nemerow index showed that less than 3% of the samples were slightly polluted, indicating good environmental quality. But the accumulated pollution of Cd and Hg was relatively high in some areas which was mainly affected by the high density of the industry. The farmland soils in Beijing suburbs were found to be suitable for farming, but a small percentage of the soils exceeded the green standard; Cd and Hg levels require special attention.

Increase in industrial growth, urban and agricultural pollution, with consequent impacts on aquatic ecosystems are a major focus of research worldwide. Still, not many studies assess the impacts of contamination through in situ studies, using native species, also considering the influence of seasonality on their responses. This study aimed to evaluate the water quality of the basin of the Upper Iguaçu River, the main source of water supply to Curitiba, a major capital of Southern Brazil, and its Metropolitan area. Several biomarkers were evaluated after in situ exposure of the native catfish Rhamdia quelen inside cages for 7 days. Ten study sites were chosen along the basin, based on a diffuse gradient of contamination, corresponding to regions upstream, downstream, and within \"great Curitiba\". In each site, fish were exposed in Summer and Winter. The complex mixture of contaminants of this hydrographic basin generated mortality, and ion-, osmoregulatory and respiratory disturbances in the catfish as, for example, reduction of plasma osmolality and ionic concentrations, increased hematocrit levels and gill water content, altered branchial and renal activities of the enzyme carbonic anhydrase, as well as raised levels of plasma cortisol and glucose. Biomarkers were mostly altered in fish exposed in Great Curitiba and immediately downstream. There was a notable influence of season on the responses of the jundiá. A multivariate redundancy analysis revealed that the best environmental variables explained 30% of the variation in biomarkers after controlling for spatial autocorrelation. Thus, this approach and the chosen parameters can be satisfactorily used to evaluate contamination environments with complex mixtures of contaminants, in other urban basins as well.

Knowledge on baseline values of stress biomarkers in natural conditions is urgent due to the need of reference values for monitoring purposes. Here we assessed the cellular stress response of the chiton Chaetopleura angulata in situ. Biomarkers commonly used in environmental monitoring (heat shock protein 70kDa, total ubiquitin, catalase, glutathione-S-transferase, superoxide-dismutase, lipid peroxidation) were analyzed in the digestive system, gills and muscle of C. angulata, under spring and summer conditions in order to assess seasonal tissue-specific responses. Season had an effect on all targeted organs, especially affecting the digestive system which displayed clear seasonal clusters. The respective Integrated Biomarker Response (IBR) showed a 7.2-fold seasonal difference. Muscle and gills showed similar IBRs between seasons making them appropriate organs to monitor chemical pollution as they were less responsive to seasonal variation. The most stable biomarkers in these organs were ubiquitin and superoxide-dismutase thus being reliable for monitoring purposes.